Non-adherence to antiretroviral therapy is a pervasive problem that limits the effectiveness of these drugs in both the treatment and pre-exposure prophylaxis of HIV infection. Although therapeutic drug monitoring (TDM) can be used to characterize adherence to antiretroviral therapy, current approaches are expensive and often require shipping samples to centralized laboratories. The expense, operational challenges, and delays associated with TDM limits the utility of this approach especially in the developing world. In our application, we propose to develop an aptamer based urine or saliva point-of-care (POC) diagnostic that could be used to detect antiretroviral drugs in these respective matrices. Development of a urine based POC that did not require expensive laboratory equipment and that could provide instantaneous results would be highly innovative and represent a significant paradigm shift in TDM. In addition, the chemistry and process research that underpins this proposal has novel elements but if successful would also be broadly applicable to many other therapeutic areas. Our specific aims in this application are as follows. Specific Aim 1 is to isolae and screen candidate aptamers for their ability to recognise key antiretrovirals used in treatment and prevention of HIV infection. Specific Aim 2 is to develop and evaluate readout platforms for incorporation into a prototype test device. Specific Aim 3 is to conduct a tail study to characterize the performance characteristics of the aptamer diagnostic in urine samples collected after cessation of dosing with antiretrovirals. Collectively, these specific aims would generate a prototype product that could be transferred to a diagnostics company for commercial development.